Medication is frequently stored in a capsule and administered to a subject who swallows the capsule. The medication passes through the intestinal wall and enters the blood of the subject.
US Patent Application Publication 2004/0253304 to Gross et al., which is incorporated herein by reference, describes apparatus for drug administration, including an ingestible capsule. The capsule includes a drug, stored by the capsule. An environmentally-sensitive mechanism is adapted to change a state thereof responsive to a disposition of the capsule within a gastrointestinal tract of a subject. The Gross et al. publication describes a driving mechanism, that in response to a change of state of the environmentally-sensitive mechanism, is adapted to drive the drug directly through an endothelial or an epithelial layer of the gastrointestinal tract.
US Patent Application Publication 2004/0267240 to Gross et al., which is incorporated herein by reference, describes apparatus for drug administration, including an ingestible capsule, which includes a drug, stored by the capsule, and an environmentally-sensitive mechanism, adapted to change a state thereof responsively to a disposition of the capsule within a gastrointestinal (GI) tract of a subject. The capsule further includes first and second electrodes, and a control component, adapted to facilitate passage of the drug, in response to a change of state of the environmentally-sensitive mechanism, through an epithelial layer of the GI tract by driving the first and second electrodes to apply a “low intensity time-varying” (LITV) signal.
US Patent Application Publication 2005/0058701 to Gross et al., which is incorporated herein by reference, describes apparatus for drug administration, including an ingestible capsule, which includes a drug, stored by the capsule, and an environmentally-sensitive mechanism, adapted to change a state thereof responsively to a disposition of the capsule within a gastrointestinal (GI) tract of a subject. The capsule further includes first and second electrodes, and a control component, adapted to facilitate passage of the drug, in response to a change of state of the environmentally-sensitive mechanism, through an epithelial layer of the GI tract, by driving the first and second electrodes to apply a series of pulses at a current of less than about 5 mA, at a frequency of between about 12 Hz and about 24 Hz, and with a pulse duration of between about 0.5 milliseconds and about 3 milliseconds.
US Patent Application Publication 2006/0178557 to Mintchev et al. describes a method and apparatus for permitting capsule imaging of organs having larger lumens without tumbling, and includes an outer shell surrounding the capsule that targets the colon, as an example. Once the colon has been reached, the shell breaks or dissolves, and allows expansion of expandable materials attached to each end of the capsule, thereby stabilizing the capsule in the targeted organ, while permitting it to be moved by peristalsis and/or other means for locating the capsule. Imagers and light emitting diodes (LEDs) are activated during the expansion process, and enable overlapping of images. The capsule is moved through the colon, taking images at chosen frame rates with data being wirelessly transmitted by means of an RF transmitter, and is eventually expelled from the body.
U.S. Pat. No. 7,009,634 to Iddan describes a system and method for obtaining in vivo images. The system contains an imaging system and an ultra low power radio frequency transmitter for transmitting signals from the complementary metal oxide semiconductor (CMOS) imaging camera to a receiving system located outside a patient. The imaging system includes at least one CMOS imaging camera, at least one illumination source for illuminating an in vivo site, and an optical system for imaging the in vivo site onto the CMOS imaging camera.
U.S. Pat. No. 6,235,313 to Mathiowitz et al. describes bioadhesive polymers in the form of, or as a coating on, microcapsules containing drugs or bioactive substances which may serve for therapeutic, or diagnostic purposes in diseases of the gastrointestinal tract. The polymeric microspheres are all described as having a bioadhesive force of at least 11 mN/cm.sup.2 (110 N/m.sup.2). Techniques for the fabrication of bioadhesive microspheres, as well as a method for measuring bioadhesive forces between microspheres and selected segments of the gastrointestinal tract in vitro are also described. This quantitative method is described as providing a means to establish a correlation between the chemical nature, the surface morphology and the dimensions of drug-loaded microspheres on one hand and bioadhesive forces on the other, allowing the screening of the most promising materials from a relatively large group of natural and synthetic polymers which, from theoretical considerations, should be used for making bioadhesive microspheres.
US Patent Application Publication 2004/0180086 to Ramtoola describes gastro-retentive dosage forms for prolonged delivery of levodopa and carbidopalevodopa combinations. The dosage forms comprise a tablet containing the active ingredient and a gas-generating agent sealed within an expandable, hydrophilic, water-permeable and substantially gas-impermeable membrane. Upon contact with gastric fluid, the membrane expands as a result of the release of gas from the gas-generating agent in the tablet. The expanded membrane is described as being retained in the stomach for a prolonged period of time, up to 24 hours or more, during which period the active ingredient is released from the tablet providing delivery of levodopa to the site of optimum absorption in the upper small intestine.
An article entitled “Gastrointestinal patch systems for oral drug delivery” by Tao et al. provides a review of gastrointestinal patch systems with integrated multifunctions. Several gastrointestinal patch systems are described as providing bio-adhesion, drug protection and unidirectional release. This combination of function is described as improving the overall oral bioavailability of large molecules that can currently be delivered only by injection, for example, epoetin-alpha and granulocyte-colony-stimulating factor, which are commonly used to treat chemotherapy-associated anemia and leukopenia, respectively. Furthermore, self-regulated release and cell-specific targeting are described as providing additional “smart” characteristics to this innovative therapeutic platform.
The following references may be of interest:    PCT Publication WO 05/105053 to Gross et al.    U.S. Pat. No. 6,958,034 to Iddan    U.S. Pat. No. 6,685,962 to Friedman et al.    U.S. Pat. No. 7,160,258 to Imran et al.    US Patent Application Publication 2004/0050394 to Jin    US Patent Application Publication 2006/0276844 to Alon et al.    US Patent Application Publication 2008/0063703 to Gross et al.    US Patent Application Publication 2008/0275430 to Belsky et al.    US Patent Application Publication 2008/0188837 to Belsky et al.    US Patent Application Publication 2003/0153866 to Long et al.    “Expandable gastroretentive dosage forms,” by Klausner et al., Journal of Controlled Release 90 (2003) 143-162